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771.
772.
In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation.  相似文献   
773.
The disposal of hazardous crude oil tank bottom sludge (COTBS) represents a significant waste management burden for South Mediterranean countries. Currently, the application of biological systems (bioremediation) for the treatment of COTBS is not widely practiced in these countries. Therefore, this study aims to develop the potential for bioremediation in this region through assessment of the abilities of indigenous hydrocarbonoclastic microorganisms from Libyan Hamada COTBS for the biotreatment of Libyan COTBS-contaminated environments. Bacteria were isolated from COTBS, COTBS-contaminated soil, treated COTBS-contaminated soil, and uncontaminated soil using Bushnell Hass medium amended with Hamada crude oil (1 %) as the main carbon source. Overall, 49 bacterial phenotypes were detected, and their individual abilities to degrade Hamada crude and selected COBTS fractions (naphthalene, phenanthrene, eicosane, octadecane and hexane) were evaluated using MT2 Biolog plates. Analyses using average well colour development showed that ~90 % of bacterial isolates were capable of utilizing representative aromatic fractions compared to 51 % utilization of representative aliphatics. Interestingly, more hydrocarbonoclastic isolates were obtained from treated contaminated soils (42.9 %) than from COTBS (26.5 %) or COTBS-contaminated (30.6 %) and control (0 %) soils. Hierarchical cluster analysis (HCA) separated the isolates into two clusters with microorganisms in cluster 2 being 1.7- to 5-fold better at hydrocarbon degradation than those in cluster 1. Cluster 2 isolates belonged to the putative hydrocarbon-degrading genera; Pseudomonas, Bacillus, Arthrobacter and Brevundimonas with 57 % of these isolates being obtained from treated COTBS-contaminated soil. Overall, this study demonstrates that the potential for PAH degradation exists for the bioremediation of Hamada COTBS-contaminated environments in Libya. This represents the first report on the isolation of hydrocarbonoclastic bacteria from Libyan COTBS and COTBS-contaminated soil.  相似文献   
774.
The effect of two components of male courtship, color and display behavior, on female choice of mates was investigated in the guppy (Poecilia reticulata). Computer-modified videos were constructed to determine the relative importance of a static trait, the presence or absence of carotenoid pigment (C and NC), and a dynamic trait, high and low display rate (HD and LD), on female response. Females were given a choice between all combinations of male display and color in a binary choice design. Preference was determined by the time females spent visually inspecting the animation. Females preferred animations with high display rates when both animations displayed color (CHD vs CLD), but not in the absence of color (NCHD vs NCLD). Equal numbers of females chose the color/low-display animation and the no-color/high-display animation when the two were paired. Conversely, color became a criterion of choice when both animations showed a low display rate (CLD vs NCLD), but not when both displayed at a high rate (CHD vs NCHD). These results suggest that females use both static and dynamic traits to evaluate males, but their rankings are affected by the choices available. Results of these experiments provide insights into how females use multiple traits to assess males.  相似文献   
775.
Abstract: An ecosystem management program and assessment process was developed to standardize an ecosystem-based approach to protecting the ecological integrity of Ontario's national parks. The elements of the ecosystem management program collectively represent the dominant planning and technical aspects of ecosystem management. Within the program, 11 specific products—ecosystem conservation plan, greater park ecosystem inventory and analysis, greater park ecosystem scope, area of cooperation, stakeholder analysis, partnership group management guidelines, scientific research program, ecological indicators, ecological integrity monitoring program, information network, and communication strategy—are considered requisite tools to improve the scientific understanding required for park management within the context of greater park ecosystems and to increase communication and coordination among governments and citizens to improve decision making. The formal process uses evaluation criteria associated with the 11 products to assess progress in developing an ecosystem management program and the content of the related products. The assessment process, which provides comprehensive identification of a park's specific ecosystem management needs, has been applied to all national parks in Ontario in the past year, which has had the immediate effect of refining their ecosystem management programs.  相似文献   
776.
Abstract: Studies of fragmented landscapes, especially in the tropics, have traditionally focused on the native fragments themselves, ignoring species distributions in surrounding agricultural or other human-dominated areas. We sampled moth species richness within a 227-ha forest fragment and in four surrounding agricultural habitats (coffee, shade coffee, pasture, and mixed farms) in southern Costa Rica. We found no significant difference in moth species richness or abundance among agricultural habitats, but agricultural sites within 1 km of the forest fragment had significantly higher richness and abundance than sites farther than 3.5 km from the fragment. In addition, species composition differed significantly between distance classes ( but not among agricultural habitats), with near sites more similar to forest than far sites. These results suggest that (1) different agricultural production regimes in this region may offer similar habitat elements and thus may not differ substantially in their capacities to support native moth populations and (2) that the majority of moths may utilize both native and agricultural habitats and move frequently between them, forming "halos" of relatively high species richness and abundance around forest fragments. Correlations between species richness and the amount of nearby forest cover, measured over circles of various radii around the sites, suggest that halos extend approximately 1.0–1.4 km from the forest edge. The extent of these halos likely differs among taxa and may influence their ability to survive in fragmented landscapes.  相似文献   
777.
To determine nutritional and social influences on life history traits and mating behavior in female langur monkeys, new long-term data for a feral population living in multi-male groups under poor nutritional conditions are presented and compared with published long-term data for the same species living in one-male groups under excellent nutritional conditions. Under poor nutritional conditions, conceptions were confined to 5 months per year, coinciding with the period of the highest mating activity. Age at first parturition, gestation periods, lactation periods, and interbirth intervals were all significantly increased resulting in a more than 50% reduced reproductive rate under poor conditions. The pattern of sexual behavior during gestation was influenced by neither nutritional nor social conditions but the frequency was higher in multi-male groups. Furthermore, estrus length was significantly increased in multi-male groups where females tended to mate with as many resident males as available. Both phenomena, together with a high percentage of sexual behavior occurring outside the mid-cycle estrus, are interpreted in the light of paternity confusion in multi-male groups in a species where infanticide by males is regularly observed. The extreme variation in life history traits and mating patterns disclosed here in one species suggests that future cross-species comparisons should strictly select datasets based on local ecological and social conditions.  相似文献   
778.
779.
Objects in the terrestrial environment interact differentially with electromagnetic radiation according to their essential physical, chemical and biological properties. This differential interaction is manifest as variability in scattered radiation according to wavelength, location, time, geometries of illumination and observation and polarization. If the population of scattered radiation could be measured, then estimation of these essential properties would be straightforward. The only problem would be linking such estimates to environmental variables of interest. This review paper is divided into three parts. Part 1 is an overview of the attempts that have been made to sample the five domains of scattered radiation (spectral, spatial, temporal, geometrical, polarization) and then to use the results of this sampling to estimate environmental variables of interest. Part one highlights three issues: first, that relationships between remotely sensed data and environmental variables of interest are indirect; second, our ability to estimate these environmental variables is dependent upon our ability to capture a sound representation of variability in scattered radiation and third, a considerable portion of the useful information in remotely sensed images resides in the spatial domain (within the relations between the pixels in the image). This final point is developed in Part 2 that explores ways in which the spatial domain is utilized to describe spatial variation in remotely sensed and ground data; to design optimum sampling schemes for image data and ground data and to increase the accuracy with which remotely sensed data can be used to estimate both discontinuous and continuous variables. Part 3 outlines two specific uses of information in the spatial domain; first, to select an optimum spatial resolution and second, to inform an image classification.  相似文献   
780.
For humanitarian organisations, accurate data are essential to identify emerging health problems and determine programme needs. We visited 45 post-emergency phase displaced persons camps and collected three months' mortality data which we compared with organisations' routine mortality reports. Organisations reported 612 deaths and we identified 741 deaths, for a mortality-reporting ratio, defined as the number of organisation-reported deaths divided by the number of investigator-identified deaths, of 83 per cent. For the majority of camps which under-reported deaths, mortality reporting ratios were significantly higher for women than men, and for camps with central mortality registers rather than those without. In the few camps which over-reported deaths, these occurred primarily among children younger than five years of age, probably due to the inclusion of abortions and stillbirths. Despite the overall under-reporting of deaths by humanitarian organisations, the existing health information systems appear to estimate mortality rates adequately in these post-emergency camps. However, organisations should improve the precision and completeness with which they report the characteristics of deaths in order to provide valuable data to target their programmes at the most vulnerable people.  相似文献   
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